Algorithms for processing spatial information

Pairs of stimuli taken from a psychometric measure of spatial aptitude were shown to 9-year-olds, 13-year-olds, and adults. The stimuli in pairs were (a) either identical or mirror images, and (b) presented in orientations that differed by 0-150 degrees. Individuals judged, as rapidly as possible, if the stimuli in a pair would be identical or mirror images if presented at the same orientation. In Experiment 1, in which the stimuli were letter-like characters, at all ages most persons solved the problems using an algorithm in which an individual encodes the stimuli in working memory, mentally rotates one stimulus to the orientation of the other, compares them to determine if they are identical, and responds. In Experiment 2, the stimuli were multielement flags; here, the modal algorithm for both 9- and 13-year-olds differed from the previously described algorithm in that if the comparison process revealed that the stimuli were dissimilar, individuals did not respond immediately, but continued processing until a self-imposed deadline was reached. Among adults, the modal algorithm was the same one used in Experiment 1. Results are discussed in terms of the roles of encoding in contributing to the use of a particular algorithm.     

The effects of vicarious experience on pain termination and work avoidance: a replication

Clinical research suggests that vicarious experience plays an important role in the development of pain behavior but only one experimental study has shown that prior exposure to a model's reaction to a pain stimulus affects a subject's subsequent reaction to that stimulus. The purpose of the present investigation was to replicate this experimental study. Twenty-two experimental subjects viewed a film of a model in pain who either terminated a work task quickly (high-avoidant) or not quickly (low-avoidant). Subjects then performed the same work task while exposed to the same pain stimulus. The results indicated that subjects exposed to the high-avoidant model tolerated the pain stimulus for significantly fewer seconds and did significantly less work compared to the low-avoidant model subjects. As predicted, no group differences were observed on work speed or work accuracy. The results provide further evidence for the role of vicarious processes in the development of reactions to painful stimuli.     

Explicit syllable and phoneme segmentation in the young child

To write a language, one must first abstract the unit to be used from the acoustic stream of speech. Writing systems based on the meaningless units, syllables and phonemes, were late developments in the history of written language. The alphabetic system, which requires abstraction of the phonemic unit of speech, was the last to appear, evolved from a syllabary and, unlike the other systems, was apparently invented only once. It might therefore be supposed that phoneme segmentation is particularly difficult and more difficult, indeed, than syllable segmentation. Speech research suggests reasons why this may be so. The present study provides direct evidence of a similar developmental ordering of syllable and phoneme segmentation abilities in the young child. By means of a task which required preschool, kindergarten, and first-grade children to tap out the number of segments in spoken utterances, it was found that, though ability in both syllable and phoneme segmentation increased with grade level, analysis into phonemes was significantly harder and perfected later than analysis into syllables. The relative difficulties of the different units of segmentation are discussed in relation to reading acquisition.     

False physiological feedback and emotion: Experimenter demand and salience effects

Four experiments examined the hypothesis that the Valins (1966) false physiological feedback effect with attractiveness ratings of slides is due to experimenter demand. Experiments 1 and 2 showed significant feedback effects with 5-sec feedback periods, previously reported by Barefoot and Straub (1971) to be too brief a time to search the slides for a cause of the apparent physiological arousal. Experiments 3 and 4 had 17 variations of instructions (emotional, nonemotional), stimuli (slides of people, scenic tourist slides), and type of feedback information (heart rate, eyeblink, or none). The typical false feedback effect was found under many conditions that did not seem to meet the presumptive attributional requirements for the effect. In Experiment 4, only subjects who said they were supposed to rate feedback slides higher showed the effect, regardless of instructions, stimuli, or type of feedback. The overall results are interpreted in terms of experimenter demand and stimulus salience effects.     

Bilateral transfer in mentally retarded children of ages 7 to 17 years

The purpose of this study was to describe the effect of age on bilateral transfer of mildly mentally retarded girls (IQs of 70 to 90) after practice on a 45-rpm rotary pursuit task. Subjects were 96 girls from 7 to 17 yr. old. Each performed 14 trials on a rotary pursuit task (30-sec. trials, 10 sec. between trials), half performing the first seven trials with the nonpreferred hand, using the preferred hand on the next seven trials. The order was reversed for the remaining subjects. Nonsignificant differences between Trial 1 scores of the two groups indicated that the task was novel. Trial 1 scores of both groups were positively associated with age (r = 0.5). There was no transfer to preferred hand, with negative transfer occurring to the nonpreferred hand. It was concluded that, for the task used in this study, mentally retarded girls do not experience positive bilateral transfer as do normal, age-matched girls.     

Using digitized auditory stimuli on the Macintosh computer

Hardware/software packages that digitize sound on the Apple Macintosh can help researchers prepare and present auditory materials needed for their experiments. Common features and benefits of commercially available sound digitizing packages are discussed in terms of some possible applications to cognitive psychology experiments.     

On the partitioning of squared Euclidean distance and its applications in cluster analysis

The partitioning of squared Eucliean distance between two vectors in M-dimensional space into the sum of squared lengths of vectors in mutually orthogonal subspaces is discussed and applications given to specific cluster analysis problems. Examples of how the partitioning idea can be used to help describe and interpret derived clusters, derive similarity measures for use in cluster analysis, and to design Monte Carlo studies with carefully specified types and magnitudes of differences between the underlying population mean vectors are presented. Most of the example applications presented in this paper involve the clustering of longitudinal data, but their use in cluster analysis need not be limited to this arena.     

Sex differences in the structure of intelligence: A confirmatory factor analysis

The LISREL model of Jöreskog and Sörbom was used to perform a comparative factor analysis on intelligence data from four sex by generation groups. The covariance matrices for 10 psychometric ability measures were used to isolate Spatial and Verbal Intelligence factors. Results from a series of factor analysis models indicated substantial invariance in the factor pattern and factor covariance matrices, although the hypothesis of complete invariance in factor pattern was rejected. The groups did differ in observed and unique variances. The results were basically consistent with the hypothesis that males and females have similar intellectual structure, which would have been obscured had standardized factor analysis been employed. There were also sex and generation differences in the Spatial and Verbal factor means.     

Differences in matching-to-sample performance with element and compound sample stimuli in pigeons

This series of experiments examined zero-delay matching-to-sample performance in pigeons with element and compound sample stimuli. In Experiment 1, compound sample stimuli were consistently followed by compound comparison stimuli and matching accuracy during testing was equivalent to element sample-element comparison trials on the color dimension. In Experiment 2, element comparisons suddenly introduced following compound samples produced a decrement on the line dimension only. Subsequent testing at various sample durations revealed higher matching accuracy following element samples than following compound samples on both the color and line-tilt dimensions. Experiment 3 replicated the results of Experiments 1 and 2 and also demonstrated that the superiority of element over compound matching performance remains constant over the sample durations tested. In Experiment 4 testing at sample durations up to 30 sec produced an overall decrement in matching performance, but again the element vs compound matching difference remained constant. The stimulus-generalization decrement hypothesis provided a better explanation of these results than either the information-overload hypothesis or the rule hypothesis.